Wiring Schematic Diagram

This is a 3-input mic preamplifier circuit using IC LM348. The LM348 is a high gain, internally compensated quad operational amplifier with a class AB output stage. The IC has very low input supply current and operates from a dual power supply.

Out of the four op-amps inside the IC LM348, IC1a, IC1b and IC1c are wired as non inverting amplifiers and they serve as the input amplifiers for the corresponding mic channels. The output of these three amplifiers are tied together and connected to the inverting input of the IC1a which is wired as an inverting amplifier. IC1a mixes the signals from each channel and also works as the output stage.

Here is a LM1036 stereo tone control circuit which build based on IC LM1036. This circuit will controll bass/treble level tone, volume and balance between right channel and left channel (input 1 and 2 ). You may use this circuit for stereo applications such as car radio, TV and audio systems, mp3 player, dvd player, ipod and more. An additional control input allows loudness compensation to be simply effected. The circuit should be works with supply voltage 9V to 15V DC.

Each tone response is defined by a single capacitor chosen to give the desired characteristic. By changing the values of capacitor connected to tone controlling unit, you can control bass and treble levels. pin 3 and pin 18 of IC are for treble and pin 6 and pin 15 for bass.

This is a low noise preamplifier circuit for dynamic microphones. The circuit is based on the Op-Amp UA739. The uA739 is a dual audio operational amplifier with high gain and excellent stability. Out of the two opamps available in the IC, only one is used here.

The audio signals from the microphone are coupled to the non inverting input of IC1 through the capacitor C1 and resistor R1. C1 performs input DC decoupling. The R1, C2 network bypasses the unwanted high frequency signals from the microphone. A fraction of the output is fed back to the inverting input in order to prevent oscillations and ensure better stability. The input impedance of this circuit is around 50K.This amplifier can handle signal from 20Hz to 20 KHz, which makes it excellent for audio applications.

LA3600 graphic equalizer circuit shown here. This circuit very suitable for applications like portable stereo, radio sets, home theater systems, car audio systems etc.

In the circuit capacitors C1, C3, C5, C7 and C9 are used to fix the resonance frequency of the corresponding bands. Capacitors C2, C4, C6, C8, C10 and C15 are the input capacitors and increasing the value of these capacitors will increase the low frequency response. Capacitor C13 is a decoupling capacitor and C14 is a power supply filter circuit. C12 is the output capacitor and resistor R6 limits the supply current. Gain of each band can be adjusted by using the corresponding potentiometers R1 to R5

This preamplifier circuit suitable for high impedance type electric guitar.The circuit is based on a UA 741 op-amp. The UA741 is wired as a non-inverting amplifier.The POT R1 can be used as a volume controller.The POT R6 can be used as tone controller.The switch S1 is used to produce “brilliant” or “soft” tonal effects